Fuel Hose/Pipes Assembly Replacement Steel Fuel Pipe Repair

Steel fuel lines - These are welded steel tubes, meeting GM specifications 124-M, or its equivalent. The fuel feed line is 3/8 inches diameter and the fuel return line is 5/16 inches diameter. Do not use copper or aluminum tubing to replace steel tubing. Those materials do not have satisfactory durability to withstand normal vehicle vibration.

Coupled hose - Do not repair the hoses. Replace them only as an assembly.

Uncoupled hose - Use only reinforced fuel resistant hose, made of Fluoroelastomer material. Do not use a hose within 4 inches (100 mm) of any part of the exhaust system, or within 10 inches (2154 mm) of the catalytic converter. The hoses inside diameter must match the outside diameter of the steel tubing.

Clamps - These are stainless steel, screw bank-type clamps, #2494772, or equivalent.

Steel Fuel Line Repair

1. Cut a piece of fuel hose 4 inches (100 mm) longer than the section of line to be removed. If you remove more than 6 inches (152 mm), use a combination of steel pipe and hose. The hose length should not be more than 10 inches total.
2. With a tube cutter, cut a section of the pipe to replace. Use the first step on the reamer to form a bead on the ends of the pipe and also on the new section of pipe, if used.
3. Slide the hose clamps onto the pipe and push the hose 2 inches (51 mm) onto each portion of the fuel pipe. Tighten a clamp on each side of the repair.
4. Secure fuel line to the frame.
5. Check for leaks.

Fuel Hose/Pipes Assembly Replacement Vapor Pipe - 4DR Utility

Removal Procedure

Notice: 

•	Do not attempt to repair sections of nylon pipes. Replace damaged nylon pipes.

•	Replace the vapor pipes with original equipment or parts that meet GM specifications.

•	Replace the vapor hoses with original equipment or parts meeting GM specifications. Use only reinforced fuel-resistant hose identified with the word Fluoroelastomer or GM 6163M on the hose.

1. Remove the hardware retaining section of the pipe to be replaced (2). Note the location of attaching hardware for installation.
2. Remove the section of the pipe and hoses (1).
3. Inspect the hoses for cuts, swelling, cracks and distortion. Replace as required.
4. Inspect the pipes for holes, kinks, and cracks. Replace the sections as required.

Installation Procedure

Important: 

•	Secure the pipes and hoses to prevent chafing.

1. Install the section of the pipe and hoses (1).
2. Install the hardware retaining section of the pipe being replaced (2).

Fuel Hose/Pipes Assembly Replacement Vapor Pipe - Ex. 4DR Utility

Removal Procedure

Notice: 

•	Do not attempt to repair sections of nylon pipes. Replace damaged nylon pipes.

•	Replace the vapor pipes with original equipment or parts that meet GM specifications.

•	Replace the vapor hoses with original equipment or parts meeting GM specifications. Use only reinforced fuel-resistant hose identified with the word Fluoroelastomer or GM 6163M on the hose.

1. Remove the hardware retaining section of the pipe to be replaced. Note the location of attaching hardware for installation.



2. Remove the fuel (1) and vapor (2) sections of the pipe.
3. Inspect the pipes for cuts, swelling, cracks and distortion. Replace as required.
4. Inspect the pipes for holes, kinks, and cracks. Replace the sections as required.

Installation Procedure

Important: 

•	Secure the pipes and hoses to prevent chafing.

1. Install the fuel (1) and vapor (2) sections of the pipe.
2. Install the hardware retaining section of the pipe being replaced.

Fuel Hose/Pipes Assembly Replacement Fuel Pipes - 4DR Utility

Removal Procedure

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

1. Disconnect the negative battery cable.
2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .



3. Disconnect the fittings at the engine compartment fuel feed and return pipes.
4. Disconnect the fuel pipe attaching hardware.
5. Disconnect the fuel feed and return pipe nuts at the fuel inlet and fuel outlet assembly.
6. Disconnect the fuel feed and return pipes and O-rings. Discard O-rings.
7. Remove the fuel tank.

•	Refer to Fuel Tank Replacement (Suburban) for the Suburban.

•	Refer to Fuel Tank Replacement (Tahoe/Yukon) for the Tahoe/Yukon.

•	Refer to Fuel Tank Replacement (Pick-up - Side Tank) for the Pick-up.

•	Refer to Fuel Tank Replacement (Extended Cab - Side Tank) for the Extended Cab.

•	Refer to Fuel Tank Replacement (Cab and Chassis - Side Tank) for the Cab and Chassis with a side tank.

•	Refer to Fuel Tank Replacement (Cab and Chassis - Rear Tank) for the Cab and Chassis with a rear tank only.

•	Refer to Fuel Tank Replacement for the 4DR Utility.




8. Disconnect the fuel feed and vapor hoses. On 4DR Utility, the quick-connect fittings at the fuel sender assembly. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
9. Remove the hardware retaining section of pipe to be replaced. Note location of attaching hardware for installation.
10. Remove the section of pipe and hoses.
11. Remove rust or burrs from the engine compartment fuel pipes by the following procedure:

11.1.

Use emery cloth in a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface.

11.2.

Using a clean shop towel, wipe off the male tube ends.

11.3.

Inspect all the connectors for dirt and burrs. Clean or replace the components/assemblies as required.

Installation Procedure

Caution: In order to reduce the risk of fire and personal injury, before connecting fuel pipe fittings, always apply a few drops of clean engine oil to the male pipe ends.

This will ensure proper reconnection and prevent a possible fuel leak.

During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

1. Install the new O-rings on the engine fuel feed and return pipes.



2. Connect the fuel feed and return pipes to the fuel injection unit. Finger tighten only.
3. Connect the fuel pipe attaching hardware.

Tighten
Fuel pipe attaching nuts to 27 N·m (20 lb ft) using a back-up wrench.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

4. Position new fuel pipe harness in original location and fuel pipe harness attaching hardware.
5. Remove protective caps from one end of both fuel pipes. Leave caps on other end of pipes to prevent dirt from entering.
6. Apply a few drops of clean engine oil to the male connector tube ends.



7. Connect the quick-connect fittings at the fuel feed and pipe near the in-line filter and at the fuel sender assembly. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
8. Install the fuel tank and attaching hardware if the tank was removed.
9. Tighten the fuel filler cap.
10. Connect the negative battery cable.
11. Check for fuel leaks.

11.1.

Turn the ignition switch to the ON position for 2 seconds.

11.2.

Turn the ignition switch to the OFF position for 10 seconds.

11.3.

Again, turn the ignition switch to the ON position.

11.4.

Check for fuel leaks.

Fuel Hose/Pipes Assembly Replacement Fuel Pipes - Ex. 4DR Utility

Removal Procedure

1. Disconnect the negative battery cable.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure .



3. Disconnect the fittings at the engine compartment fuel feed and return pipes.
4. Disconnect the fuel pipe attaching hardware.
5. Disconnect the fuel feed and return pipe nuts at the fuel inlet and fuel outlet assembly.
6. Disconnect the fuel feed and return pipes and O-rings. Discard O-rings.
7. Remove the fuel tank.

•	Refer to Fuel Tank Replacement (Suburban) for the Suburban.

•	Refer to Fuel Tank Replacement (Tahoe/Yukon) for the Tahoe/Yukon.

•	Refer to Fuel Tank Replacement (Pick-up - Side Tank) for the Pick-up.

•	Refer to Fuel Tank Replacement (Extended Cab - Side Tank) for the Extended Cab.

•	Refer to Fuel Tank Replacement (Cab and Chassis - Side Tank) for the Cab and Chassis with a side tank.

•	Refer to Fuel Tank Replacement (Cab and Chassis - Rear Tank) for the Cab and Chassis with a rear tank only.

•	Refer to Fuel Tank Replacement for the 4DR Utility.




8. Disconnect the fuel feed and vapor hoses.
9. Remove the hardware retaining section of pipe to be replaced. Note location of attaching hardware for installation.
10. Remove the section of pipe and hoses.
11. Remove rust or burrs from the engine compartment fuel pipes by the following procedure:

11.1.

Use emery cloth in a radial motion with the fuel pipe end in order to prevent damage to the O-ring sealing surface.

11.2.

Using a clean shop towel, wipe off the male tube ends.

11.3.

Inspect all the connectors for dirt and burrs. Clean or replace the components/assemblies as required.

Installation Procedure

Caution: In order to reduce the risk of fire and personal injury, before connecting fuel pipe fittings, always apply a few drops of clean engine oil to the male pipe ends.

This will ensure proper reconnection and prevent a possible fuel leak.

During normal operation, the O-rings located in the female connector will swell and may prevent proper reconnection if not lubricated.

1. Install the new O-rings on the engine fuel feed and return pipes.



2. Connect the fuel feed and return pipes to the fuel injection unit. Finger tighten only.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

3. Connect the fuel pipe attaching hardware.

Tighten
Fuel pipe attaching nuts to 27 N·m (20 lb ft) using a back-up wrench.

4. Position new fuel pipe harness in original location and fuel pipe harness attaching hardware.
5. Remove protective caps from one end of both fuel pipes.

Leave caps on other end of pipes to prevent dirt from entering.

6. Apply a few drops of clean engine oil to the male connector tube ends (1).



7. Connect the quick-connect fittings at the fuel feed and pipe near the in-line filter and at the fuel sender assembly. Refer to Quick Connect Fitting(s) Service (Metal Collar) .
8. Install the fuel tank and attaching hardware if the tank was removed.
9. Tighten the fuel filler cap.
10. Connect the negative battery cable.
11. Check for fuel leaks.

11.1.

Turn the ignition switch to the ON position for 2 seconds.

11.2.

Turn the ignition switch to the OFF position for 10 seconds.

11.3.

Again, turn the ignition switch to the ON position.

11.4.

Check for fuel leaks.